Electrical hot plate



Aug. 17, 1937. w W HlcKs 2,090,122

ELECTRICAL HOT PLATE Filed Oct. 22, 1955 F'IE ZE Patented Aug. 17, 1937 UNITED4 STATES PATENT OFFICE ELECTRICAL HOT PLATE William Wesley Hicks, San Francisco, Calif.

Application @ctober 22, 1935, Serial No. 46,106 s claims. loi. zie- 37) This invention relates generally to an electrical hot plate of the type utilized in conjunction with electrical ranges and like electrical appliances.

i It is an object of the invention to provide an improved electrical hot plate of the semi-open face type, in which a ceramic form carrying eX= posed resistance conductors, is provided with a foraminated protective covering. lt is a Eealll ture of the present invention that the protective covering will not warp or buckle, but will at all times afford a fiat surface for engaging the bottoms of cooking utensils.

Another object of the invention is to provide l5 an electrical hot plate in which the ceramic form will be adequately supported for all opern ating temperatures.

Further objects of the invention will appear from the following description in which the pre-= 29 ferred embodiment of the invention has been set forth in detail in conjunction with the accompanying drawing.

Referring to the drawing:

Fig. l is a plan view, illustrating one half of a hot plate incorporating the present invention.

Fig. 2 is a view similar to Fig. 1, but looking at the bottom of the hot plate.

Fig. 3 is a cross sectional detail taken along the line 3-3 of Fig. 1.

30 The hot plate illustrated in the drawing consists of a plate-like form I0 of ceramic material, and which is annular in contour. The upper face of this form is provided with grooves Il, to accommodate the coiled resistance conductors I2. Terminals I3 and I4 are carried by the form, for making connections with current supply lines. The adapter casing I6 in which this form is disposed, is made of suitable sheet metal, and includes the annular side wall I'l, and the 40 downwardly dished bottom wall I8. The bottom wall is provided with a central opening I9,

through which liquids may drain.

In order to provide properly distributed points of contact between the ceramic form and the bottom wall'of the casing I6, means are provided as follows z-Near the outer periphery of the bottorn wall I8, there is an annular upwardly pressed portion 2I, upon which the adjacent surface of the ceramic form may rest. Adjacent the periphery of opening I9, the bottom wall isv also provided with upwardly turned lugs 22, which contact the lower side of the ceramic form in a region near the center of the plate. In place of utilizing a plurality of lugs 22, it is evident that a single annular ange may be employed, provided the ilange is formed with suitable slots or apertures for the drainage of liquid.

The terminals I3 are accommodated by the central opening I9 in the bottom wall i8. Terminals ld are accommodated by additional open- 5 ings 23. The casing is also shown provided with an annular flange 25, for supporting the plate upon the top surface 20 of an electric range.

Protection for the upper face of the ceramic form, and for the conductors i2, is anforded by lil a screen 2li. This screen is formed oi non-corrodible metal wire, which is capable of withstanding the relatively high temperature to which it is subjected. The openings through the wire screen should be sucient to avoid intercepting a major part of heat radiated from the resistance conductors and the ceramic form. HOW- ever they should be sufliciently small to enable the screen to catch larger fragments oi food, and to prevent passage of implements such as the tines of a fork, which one might attempt to insert to remove foreign material from the grooves oi the ceramic form. In order to retain the screen 21, an annular ring 28 is provided, which can be made of pressed metal, and which has a force t within the adapter casing I6. This ring is formed to provide an annular ilange 29, which overlies the peripheral edge portion of the screen. The engagement between the ilange 29 and the screen is such that while the screen is retained to prevent accidental displacement, it may expand and contract independently with respect to the ceramic form I0, and with respect to the ring 28.

The hot plate described above has many desirable features. The screen 2l does not materially decrease the eciency of heat transfer to the bottoms of cooking utensils. However the protection which it affords materially increases the useful life of the hot plate, and minimizes the possibility of short-circuiting the resistance conductors through the charrlng of food particles, as well as mechanical injury to the ceramic form. When the plate is heated even small droplets of liquid will not pass through the screen, but are immediately vaporized. Because of the manner in which the screen 21 is retained, it will not warp or buckle, but will at all times present a flat surface to the bottom of the utensils. The ceramic form is more or less full floating within the adapter casing I6, and it is supported in such a manner that it may properly carry the Weight of utensils, even when heated to relatively high temperatures.

i claim:

l. in an electrical hot plate, a plate-like form of ceramic material, said form being annular in contour and having grooves provided in its upper g face, a resistance conductor disposed within said grooves, an adapter casing in which said ceramic form is disposed, said adapter casing being formed of sheet metal and including a downwardly dished bottom wail and an annular con- 10 toured sidewall adapted to extend about the side edges of the ceramic form, said bottom wall 1 having an annular portion thereof pressed upwardly for engaging the bottom face of the ceramic form along an annular line of contact l5 spaced inwardly from but adjacent the periphery of the form, and also having supporting means for engaging the bottom face of the form at points located relatively close to the centerof the form.

2o 2. 1n an electrical hot plate, a relatively fiat 'and annular contoured adapter casing formed of sheet metal, the bottom wall of said casinghaving a central opening and being dished downwardly, an annular portion of said bottom Wall spaced 25 inwardly from but adjacent the periphery of the casing being pressed upwardly, a plate-like form of ceramic material disposed within said casing and resting upon said upwardly pressed annular portion, and additional supporting means extending upwardly from said bottom Wall in a region adjacent the opening through the same and en'- gaging the bottom face of said ceramic form.

3. In an electrical hot plate, a relatively at and annular contoured sheet metal adapter casing, said casing having a bottom wall provided with a central opening and being dished downwardly, an annular portion of said bottom Wall spaced inwardly from but adjacent the outer pe? riphery of said casing, being pressed upwardly, a plate-like form of ceramic material disposed Within said adapter casing and having its lower face engaging said annular portion, said form having grooves provided in its upper face, a resistance conductor disposed within said grooves, and additional supporting means for the central portion of the ceramic form, said last mentioned means comprising spaced members extending upwardly from points adjacent the inner pehipheral edge portion of said casing. Y a

WILLIAM WESLEY HICKS. 

